Testosterone Total, and Free Testosterone
Sample
- It is done in the serum.
- Can use heparinized plasma.
- 24 hours of the urine sample.
- Separate the serum immediately, if kept for a longer period (more than 6 hours), may get false high values.
- The sample is stable at 1 to 4 °C for one week.
- Free Testosterone is stable for 1 to 2 days at 4 °C.
- At -20 °C sample is stable for 6 months.
Precautions
- Separate serum from the cells within 6 hours otherwise there is the false elevation of the value.
- The level is high in adults in the AM sample and 25% lower in the evening sample.
- In females lower values with increase 1 to 2 days mid-cycle.
- High values after the exercise.
- Value is decreased after the overload with glucose.
- There is a slow progressive decrease after the age of 50 years.
Purpose of the test (Indications)
- This test is done in male to assess the:
- Hypogonadism.
- Cryptorchidism.
- Impotence.
- Pituitary gonadotropic function.
- Infertility.
- Precocious puberty.
- Tumor marker for the testicular tumors.
- In the female this test is done to assess:
- Hirsutism and virilizing syndrome.
- Ambiguous sex character.
- Precocious puberty.
- Tumor marker for ovarian tumors.
- Maybe part of the fertility workup of the chronic anovulatory cycle due to the polycystic ovary.
Pathophysiology
- Testosterone is the main androgen secreted by the testes and its production increases by puberty.
- Women only produce 5 to 10% of the testosterone as much produced by the male.
- Androgenic hormone includes :
- Dehydroepiandrosterone (DHEA).
- Androsterone.
- Testosterone.
- The adrenal gland produces DHEA, Cortisol, Aldosterone, and Testosterone.
- Testes produce DHEA.
- Ovaries produce DHEA.
- DHEA is a precursor of the Androstenedione precursor of Testosterone + estrogen.
- Testosterone is responsible for the development of male secondary characters.
- Testosterone secreted :
- In men by:
- Adrenal glands produce 2/3.
- Testes produce 1/3.
- In female by:
- Adrenal glands. Almost all from the adrenal glands.
- Ovaries.
- In men by:
- The pituitary gland produces LH in males and FSH in females.
- LH stimulates the Leydig cells to produce Testosterone.
- FSH Stimulates Sertoli cell to help in spermatogenesis.
- Testosterone stimulates spermatogenesis and secondary sex character.
- Testosterone Increased production :
- In Male produces premature puberty.
- In female produce masculinity (manifested by amenorrhea, and excessive growth of body hairs).
- Testosterone Increased production :
- Testosterone exists in two forms in the serum.
- In males:
- Abound fraction consists of :
- 60 to 65 % strongly bound to sex hormone-binding globulin.
- The rest most of it is loosely bound to albumin.
- Abound fraction consists of :
- In females:
- Abound fraction consists of:
- 1% is free.
- 80% bound to sex hormone-binding globulin (SHBD).
- 19% bound to albumin.
- Abound fraction consists of:
- The free fraction is 2% which is unbound to sex hormone globulin and albumin.
- In males:
- Total testosterone = Bound fraction + Free fraction.
- Free fraction is the Active form.
- Testosterone has fluctuation in the level.:
- In the male, there is a peak level early in the morning.
- In the female, there is cyclic elevation 1 to 2 days around mid-cycle.
- Serum level of testosterone :
- in male infants :
- By 2 weeks = around 25 ng/dL.
- BY 2 months = around 275 ng/dL.
- In female infants :
- By 2 weeks = around 25 ng/dL.
- By 2 months = Value decreases and remains low throughout early childhood.
- in male infants :
- Testosterone is made by :
- In males mainly by the Leydig cells which is almost 95 % of the total.
- In female :
- About 50 % is made by the conversion of DHEA in the fatty tissue.
- 30 % conversion of DHEA in the adrenal glands.
- 20 % made directly by the ovaries.
- Testosterone is metabolized in the liver and the main metabolites are:
- Androsterone.
- DHT (dihydrotestosterone).
- These are further metabolized into androstenedione and etiocholanelone.
- End metabolites are excreted through the kidneys.
- A testosterone stimulation test is done for hypogonadism. This stimulation can be done by giving clomiphene, and HCG.
- The main metabolites of adrenal, testicular, and ovarian hormones are secreted through kidneys as 17-ketosteroids.
NORMAL
Source 1
Testosterone Free
Age | pg/mL | |
Male | Female | |
Cord | 5 to 22 | 4 to 16 |
Newborn (1 to 15 days) | 1.5 to 31.0 | 0.5 to 2.5 |
1 to 3 month | 3.3 to 8.0 | 0.1 to 1.3 |
3 to5 month | 0.7 to 14.0 | 0.3 to 1.1 |
5 to 7 month | 0.4 to 4.8 | 0.2 to 0.6 |
Children | ||
6 to 9 year | 0.1 to 3.2 | 0.1 to 0.9 |
10 to 11 year | 0.6 to 5.7 | 1.0 to 5.2 |
12 to 14 year | 1.4 to 156 | 1.0 to 5.2 |
15 to 17 year | 80 to 159 | 1.0 to 5.2 |
Adult | 50 to 110 | 1.0 to 8.5 |
- To convert into SI units x 3.47 = pmol/L
Testosterone Total (blood)
Age | ng/dL | |
Male | Female | |
Cord | 13 to 55 | 5 to 45 |
Premature | 37 to 198 | 5 to 22 |
Newborn | 75 to 400 | 20 to 64 |
1 to 5 month | 1 to 177 | 1 to 5 |
6 to 11 month | 2 to 7 | 2 to 5 |
Children | ||
1 to 5 year | 2 to 25 | 2 to 10 |
6 to 9 year | 3 to 30 | 2 to 20 |
Puberty Tanner stage | ||
1 | 2 to 23 | 2 to 10 |
2 | 5 to 70 | 5 to 30 |
3 | 15 to 280 | 10 to 30 |
4 | 105 to545 | 15 to 40 |
5 | 265 to 800 | 10 to 40 |
Adult | 280 to 1100 | 15 to 70 |
Pregnancy | 3 to 4 x adult level | |
Postmenopausal | 8 to 35 |
- To convert into SI unit x 0.0347 = nmol/L
Urine
- 20 to 50 years
- Male = 50 to 135 µg/day
- Female = 2 to 12 µg/day
- >50 years
- Male = 40 to 60 µg/day
- Female = 2 to 8 µg/day
- >50 years
Source 2
Total testosterone
- Men = 3 to 10 ng/mL
- Women = <1 ng/mL
- Prepubertal boys and girls = 0.05 to 0.2 ng/mL
Source 4
Free testosterone
- Men = 50 to 210 pg/mL.
- Women = 1.0 to 8.5 pg/mL.
- Children:
- Boy = 0.1 to 3.2 pg/mL.
- Children Girl = 0.1 to 0.9 pg/mL.
- Puberty:
- Boy = 1.4 to 156 pg/mL.
- Puberty Girls = 1.0 to 5.2 pg/ml.
Total testosterone
- Men = 270 to 1070 ng/dL.
- Women = 15 to 70 ng/dL.
- Postmenopausal women = 8 to 35 ng/dL.
- Pregnant women = 3 to 4 ng/dL
Increased values of Total Testosterone is seen in:
- Male
- hyperthyroidism.
- Adrenal tumors.
- Adrenal Hyperplasia.
- Hypothalamic tumor, Pinealoma.
- Viral encephalitis.
- Testicular or extragonadal tumors where Leydig cells produce testosterone.
- Testosterone resistance syndrome.
- Female
- Adrenal neoplasm.
- Hilar cell tumor.
- Idiopathic Hirsutism.
- Trophoblastic disease during pregnancy
- Ovarian tumors
- Polycystic ovary.
Decreased Total testosterone value is seen in Male:
- Klinefelter syndrome.
- Pituitary failure leading to hypogonadism.
- Hypopituitarism may be primary or secondary.
- Orchiectomy.
- Delayed puberty.
- Down syndrome (trisomy 21).
- Cirrhosis.
- Cryptorchidism due to undescended testes.
Increased Free Testosterone is seen in Female:
- Hirsutism.
- Virilization.
- polycystic ovaries.
Decreased Free Testosterone is seen in Male:
- Hypogonadism.
- old age.